Two phase compound microwave dielectric ceramic having medium dielectric constant, and preparation method thereof

Abstract

The invention relates to a two phase compound microwave dielectric ceramic having a medium dielectric constant, and a preparation method thereof. A molar ratio composition formula of the ceramic material is xBa(Zn1 / 3Nb2 / 3)O3+(1-x)ZnNb2O6, wherein 0.25 <= x <= 0.40 and x is a mole percent. The preparation method comprises the steps of pre-synthesizing ZnNb2O6 and Ba(Zn1 / 3Nb2 / 3)O3 by a solid phase reaction of ZnO, Nb2O5 and BaCO3; weighing according to a chemical general formula; mixing; milling for two times; drying; pressing powder into cylindrical bodies by isostatic pressing; sintering for 2 h and cooling. The invention provides a novel material having a medium dielectric constant, high Q*f value and nearly zero temperature coefficient of resonance frequency. A preparation process matching with the material is provided by the invention; the microwave dielectric ceramic with good quality is obtained; and selection scope of microwave dielectric application materials is broadened.

Description

technical field [0001] The invention relates to a two-phase composite microwave dielectric ceramic with a medium dielectric constant used in microwave components such as dielectric resonators, filters, Beidou navigation antennas and military radars in communication systems and a preparation method thereof, belonging to the field of science and technology of information functional materials . Background technique [0002] Microwave dielectric ceramics refer to ceramic materials that are used as dielectric materials in the microwave frequency band and perform one or more functions. They are widely used in the field of modern communications such as resonators, filters, dielectric substrates, and dielectric waveguide circuits. the key material. With the continuous development of modern communication technology, dielectric ceramic materials used in microwave circuits generally need to meet: (1) High relative permittivity ε r To reduce device size, it is generally required that ...

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Problems solved by technology

But its resonant frequency temperature coefficient shifts a lot (τ f =-56ppm / ℃), the dielectric constant is low, which limits its practical application

Feng Gao et al. in ZnNb 2 o 6 Add 1wt%V in 2 o 5 +1wt%Bi 2 o 3 +2.5wt%CuO can reduce the sintering temperature of ceramics to 880°C, and the dielectric properties are: ε r =23.4, Q×f=46975GHz, τ f =-44.89ppm / ℃, oxide doping makes ZnNb 2 o 6 τ of f Moving in the positive direction, but it does not meet the requirements of practical applications; and the dielectric constant is low, which is not conducive to the miniaturization production of devices

Zhang Yingchun studied the Ti 4+ and Ta 5+ to ZnNb 2 o 6 The B-site ion is substituted when Ti 4+ Substitution to form ZnNb 2(1-x) Ti x o (6-3X) For ceramics, in the range of x=0.76~0.87, the temperature coefficient of resonance frequency can be adjusted to zero, but its Q×f drops significantly to 5000~10000GHz; when Ta 5+ replace Nb 5+ Form ZnNb 2(1-x) Ta 2x o 6 Ceramics, when x=0.62, have a high Q×f value, and the temperature coefficient of the resonant frequency can be adjusted to zero, but Ta is expensive, which is not conducive to mass production

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